1. Field
The present application relates generally to handheld devices with video encoding capabilities, and more specifically to systems and methods for rate control for video encoding based on motion information.
2. Background
Digital video capabilities can be incorporated into a wide range of devices, including digital cameras, digital recording devices, cellular or satellite radio telephones, personal digital assistants (PDAs), video gaming devices, video teleconferencing devices, and the like. Digital video devices implement video compression techniques, such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263 or ITU-T H.264/MPEG-4, Part 10, Advanced Video Coding (AVC), and extensions of such standards, to transmit and receive digital video information more efficiently.
During the process of real time video capturing and encoding using such a digital video device, a user may move the device quickly to switch the scene or focus. In such cases, a much smaller value for Quantization Parameter (“QP”), one of the encoding parameters, may be selected than actually needed. This leads to temporary spikes in the bit rate, followed by quick depletions of the bit budget. In order to maintain a constant bit rate, the quality of the upcoming frames is reduced after the movement. However, the subject to be captured after the movement is generally of more interest to the user, and higher video quality is desired after the movement stops.